NEWBORN URINARY CYCLIC AMP AND DEVELOPMENTAL RENAL RESPONSIVENESS TO PARATHYROID HORMONE

(1)

Abbreviations

ATP: Adenosine triphosphate

Cyclic AMP: 3’,5’-adenosine

mono-phosphate

GFR: Glomerular filtration rate

PTE:

Parathyroid extract

PTH: Parathyroid hormone

%

TRP: Percent tubular reabsorption

14

NEWBORN

URINARY

CYCLIC

AMP

AND

DEVELOPMENTAL

RENAL

RESPONSIVENESS

TO

PARATHYROID

HORMONE

Louie G. Linarelli, M.D., with the technical assistance of John Bobik and Caroline Bobik, B.S.

From the Department of Pediatrics, Mercy Hoital and Children’s Hospital of the

University of Pittsburgh

ABSTRACT. Since the renal action of parathyroid hormone is known to be mediated via

3’,5’-adeno-sine monophosphate (cyclic AMP), urinary cyclic AMP studies were used to determine proximal

tubular maturation. Ten formula fed full-term male infants showed a thirty- to sixtyfold increase

in phosphate clearance and excretion with a

three- to fourfold increase in urinary cyclic AMP

comparing their first and third day 24-hour urines (2.37 ± 0.41 to 6.93 ± 0.96 Nm/mg creatinine M. ± S.E.M. first and third days respectively).

Seven breast-fed infants showed cyclic AMP

ex-cretion of 3.6 ± 0.3 S.E.M. and 6.5 ± 0.3 S.E.M.

on Day 1 and Day 3 respectively, showing an in-significant difference to the formula-fed infants. An additional 10 formula-fed infants 5 to 10 days

of age excreted 7.0 ± 0.9 S.E.M. Nm/mg of

creatinine which is comparable to the 3 to 4 days

of age group. The threefold increase in cyclic

AMP after the first day of life may possibly

re-flect increasing parathyroid renal responsiveness.

One- and 3-day-old infants and adults were given a 1-hour parathyroid (PTH) infusion (5 U/kg/hr) with measurement of urinary cyclic AMP in time periods before and after the infusions. Peak in-creases in responses from baseline of cyclic AMP were 1.64 ± 0.34 ,7.1 ± 1.5, and 36.0 ± 0.73 Nm/

mg of creatinine M. ± range on first day, third day, and in adults respectively with similar relationships

of increasing phosphate excretion. Thus, there is

most likely a maturational renal proximal tubular

re-sponsiveness to PTH on the cellular cyclic AMP

level.

Pediatrics, 49:14, 1972, NEWBORN KIDNEY, PARA-THYROID HORMONE, CYCLIC AMP, RENAL DEvELoP-MENT.

E

VU)ENCE from numerous investigators

has shown that adenosine 3’,5’

mono-phosphate (cyclic AMP) is the intracellular mediator of the action of most hormones.l,2

In 1962, Butcher and Suther1and

demon-strated the presence of cyclic AMP in

hu-man urine. In 1967, Chase and Aurbach4

found that urinary cyclic AMP rose in

re-sponse to parathyroid hormone (PTH) in

human studies. They also demonstrated

that PTH acts by stimulating the

particu-late membrane enzyme adenyl cyclase in

both kidney proximal tubules5’#{176} and bones.7

The urinary cyclic AMP excretion in

re-sponse to PTH is renal in origin8 and cyclic

AMP has also been shown to mediate the

phosphaturic effect of PTH.9 Our studies

have been performed to compare the

excre-tion of phosphate and cyclic AMP in the

urine of newborn infants and to evaluate

the phosphaturic and cyclic AMP

respon-siveness to PTH in the first 3 days of life.

MATERIALS AND METHODS

Ten full-term male infants and seven

breast-fed infants at Mercy Hospital

nur-sery, Pittsburgh, Pennsylvania, were

se-lected for collections of 24-hour urines. Males were selected in order to insure more (Received August 16, 1971; revision accepted for publication January 13, 1972.)

Supported by Health Research and Services Foundation M-30.

ADDRESS FOR REPRINTS: (L.G.L.) Department of Pediatrics, Mercy Hospital, Pride and Locust Street, Pittsburgh, Pennsylvania 15219.

(2)

complete urine collections. At birth, follow-ing the first voided specimen, these infants were strapped with urine collecting devices for the first 24-hour urine (Day 1). Bloods

were drawn by heel stick at approximately midpoint of each 24-hour urine for calcium,

phosphate, and creatinine. The second

24-hour urine collections (Day 3) were started

between 48 and 72 hours of life to avoid

night-time blood specimens. Infants were

fasted for the first 12 hours of life then

given a glucose water feeding followed by

formula (Enfamil* ) every four hours. Parathyroid extract (PTEt ) at a dose of 5

U/kg in 1 hour (83 mU/kg/mm) was

given intravenously to two infants in the

first 24 hours and on the third to fourth day.

Three adolescent subjects were also given 5

U/kg/hr PTE infusions for 1 hour.

Intra-venous hydration of 20 cc/kg was given in

the first 60 to 120 minutes to initiate urine flow and obtain control urine collections.

Then PTE 5 U/kg with 0.5% albumin in

5% glucose was given over 1 hour.

Hydra-tion was maintained with drinking water

and intravenous 0.45% sodium chloride.

Urine collected in time periods before and

after intravenous PTE were collected for

measurements of phosphate, creatinine, and

0 Mead-Johnson Company, 2404 W.

Pennsylva-nia Street, Evansville, Indiana 47721.

t Eli Lilly Company, 307 E. McCarthy,

In-dianapolis, Indiana 46206.

TABLE I

NEWBORN 24-HouR URINARY PHOSPHATE AND CYCLIC AMP

. Patient . Weight (gm) S.A. M2 Day of Life Volume (ml) Urine Cr my/e’4 hr/

Pho$phale Cycli #{149}.AMP

L Vp mg/fl Sri

j73%J2

-L I p mg/kq/ ?ihr Cp #{149} nzl/intn/ 1.73Af’ Total Nm Nmoles/ , m2Cr Nmoles/ . mm Nmote8/ , i.,SM2

IN. ,69S 0.178 1 5 10.5 4.SO 0.93 OlO 53 5.04 004 515

S 110 3.O 35.8O 13.48 l8 197 6.15 0.14 1,915

11.U. 8,600 O.5 I

S 100 9.O 39.4 5.76 844.00 O.si 30.55 0.06 6.31 96 419 3.31 1O.6 0.07 Ol9 737 3l18

RE. 3,430 O.QO I 110 i8.8 8.55 0.13 0.06 53 1.84 0.04 417

3 180 30.6 I3.6O 7.9 1.65 l1 6.88 0.15 1,658

LO. 3.884 O.3O 1

3 18 175 iO.O 70.1 2.84 5l6.4O 0.10 18.04 0.03 3.93 9 54 0.45 0.77 0.01 0.04 68 406

K.A. 3,090 0Z00 I 7 18.9 4.67 0.18 0.05 53 .80 0.04 438

3 135 .9 3l5l9 11.79 .81 134 5.84 0.09 1,159

AL.. 3,033 0.Q30 I

3 3 220 31.9 41.7 il.i4 777.36 0.93 34.09 0.6 7.50 39 405 1l2 9.69 0.03 0.28 293 3,045

HO. 2,892 0.190 1

S 13 133 6.0 21.6 8.28 20.70 0.31 7.70 0.18 1.60 16 231 9.68 10.69 0.01 0.16 145 2,102

JO. 3,572 0.210 1 92 41.4 3.03 0.10 0.04 124 2.99 0.09 1,022

3 iSO 26.0 299.94 10.19 2.51 134 5.15 0.09 1,104

S.C. 3,515 0.210 1 35 26.6 1.73 0.06 0.02 53 1.99 0.04 437

3 128 19.1 673.28 13.47 3.66 158 8.23 0.73 1,302

ST. 2,948 0.188 1 88 26.7 3.24 0.12 0.03 36 1.35 0.01 331

3 225 26.9 227.70 8.40 2.66 143 5.30 0.10 1,315

(3)

PHOSPHATE EXCRETiON mg/24 hrs./1.73 M2

Fic. 1. Values for phosphate measurements from urines collected on Day 1 and Day 3 of life from 10 formula-fed full-term male infants. Complete data are tabulated in Table I. Urine phosphate

ex-cretion mg/24 hr/1.73 M2.

I

E

S. U

PHOSPHATE CLEARANCE

ml/min.,/ l.73M’

Fic. 2. Values for phosphate measurements from

urines collected on Day 1 and Day 3 of life from

10 formula-fed full-term male infants. Complete

data are tabulated in Table I. Phosphate clearance ml/min/1.73 M2.

cyclic AMP. Blood samples were drawn at

near midpoints of urine collections for

phosphate and creatinine.

Urine specimens were frozen until

ana-lyzed. Blood specimens were centrifuged

and analyzed immediately. Adenosine

3’,5’-monophosphate was determined by the

method of Kaneko and Field’#{176} where

cyclic AMP is converted to ATP, and ATP

is assayed by measuring the quantity of

‘4C02 evolved from glucosel-.1 4C. Isolation

of urinary cyclic AMP prior to assay was

performed as described by Chase, et al.hi

RESULTS

Data on urines collected on Day 1 and

Day 3 of life from 10 formula-fed full-term male infants is shown in Table I. The phos-phate excretion increases by fiftyfold with a

mean of 7.8 mg/24 hr/1.73 M2 on Day 1 to

231.4 mg/24 hr/1.73 M2 on Day 3 (Fig.

1). Likewise, there was a thirty- to forty-fold increase in phosphate clearance by the

third day (Fig. 2) with a mean of 0.09 ml

/min/1.73 M2 on Day 1 to 3.49 ml/min/

1.73 M2 on Day 3. There was a tendency for

the serum calcium to drop and phosphate

to rise by the third day of life, but the dif-ference was insignificant.

Twenty-four-hour urine cyclic AMP was

measured in these same 10 formula-fed

in-fants. Cyclic AMP rises from a mean of 53

Nm/24 hours to 209 Nm/24 hours

(4)

URINARY CYCLIC AMP

N MoI../24 hr..

4w

4S

3$

341 #{163}

I

ii

41

the fourfold increase in urine output, there

was a threefold increase in cyclic AMP

ex-cretion expressed as Nm/mg of creatinine.

The means are 2.37 and 6.9 Nm/mg of

creatinine on Day 1 versus Day 3

respec-tively ( Fig. 4)

.

Since it is extremely diffi-cult to insure accurate 24-hour urine collec-tions in newborn infants, errors in timing of

collections are minimized by relating the

data to creatinine excretion. There was a

tendency for the cyclic AMP excretion to

follow the phosphate excretion in many

cases but there was a lack of linear

correla-tion between the two functions. For

exam-pie, number seven was the lowest

phos-phate excretor and one of the highest cyclic AMP excretors.

Urines were collected for cyclic AMP

analysis on seven breast-fed infants on Day 1 versus Day 3. The cyclic AMP excretions were 3.6 ± 0.3 S.E.M. and 6.5 ± 0.3 S.E.M.

Nm/mg of creatinine on Day 1 and Day 3

respectively, giving an insignificant differ-ence in the formula-fed versus the

breast-fed infants. Ten formula-fed infants 5 to

10 days of age excreted 7.0 ± 0.9 S.E.M.

Nm/mg of creatinine which is a

compara-ble excretion to the 3 to 4 day age group.

Table II compares newborn infants

ver-sus adult urinary cyclic AMP excretion in

our laboratory. The cyclic AMP excretion

expressed in Nm/24 hr/1.73 M.2 on Day 1

is 442 and on Day 3 is 1,722 compared with an adult level of 4,162. The higher value in adults reflects in part the relatively greater surface area of the neonate. Average values

of 2.3 Nm/mg creatinine on Day 1

com-pared to 6.9 Nm/mg creatinine on Day 3 are

obviously significantly different. However, adult values are slightly greater than those on Day 1 (0.02 <p <0.05). Because of low glomerular filtration rate (GFR) in infants, the cyclic AMP values corrected for

creati-nine excretion are in part increased relative

to the adult values.

To test renal responsiveness to

parathy-roid hormone, parathyroid extract (PTE)

was infused intravenously at 5 U/kg for 1

hour (83 mU/kg/mm). It has previously

been shown in adult volunteers that an

in-0*81 0*83

Fm. 3. Values for cyclic AMP measurements from urines collected on Day 1 and Day 3 of life from 10 formula-fed full-term male infants. Complete data are tabulated in Table I. Urinary cyclic AMP N

moles/24 hours.

fusion of 80 mU/kg/mm of PTH produced

the maximum response of cyclic AMP

ex-cretion.8 Urines were collected at time

in-tervals before, during, and following PTE

infusion. These infusions were performed in infants the first 24 hours of age, 3 to 4 days

of age (Table III), and adolescent adult

volunteers 16 to 18 years of age (Table

IV). Figure 5 shows the delta from

base-line of phosphate studies before PTE infu-sion to peak rise which occurred in the first

2 hours after PTE infusion. Delta

phos-phate excretion expressed in milligrams per

hour is near 0 on Day 1, 8.9 on Day 3, and

31.5 in the adolescent adult. Phosphate

clearance expressed in millimeters per min-ute is 0 Day 1, 1.69 on Day 3, and 13.07 in the adults. The delta percent tubular

reab-sorption (%TRP) did not show a clear

dis-tinction in the Day 3 infant versus adults.

Control %TRP in these newborn infants

(5)

sim-I,

r

z

0*83

Ftc. 4. Values for cyclic AMP measurements from

urines collected on Day 1 and Day 3 of life from

formula-fed full-term male infants. Complete data

are tabulated in Table I. Urinary cyclic AMP N

moles/mg creatinine. 0*81

PTE INFUSION

Ezcrstlon CIsr.nc.

I

Fm. 5. Comparison of change in phosphate ex-cretion, phosphate clearance, and %TRP follow-ing parathyroid extract infusion at a dosage of 5 U/kg over 1 hour in 1- and 3-day-old infants

versus adults.

12 URINARY C’VCLIC AMP ilar to previous observations.12 Peak

in-N Mal../w4 Crs.ilnin. creases from baseline cyclic AMP in the

same patients revealed deltas of 1.64 ± 0.34

41 Nm/mg of creatinine on Day 1, 7.15 ± 1.15

on Day 3, and 36.3 ± 0.73 in the adolescent adult (Fig. 6).

DISCUSSION

Phosphate excretion and clearance has

previously been found to rise significantly

between 1 and 3 days of age.3 Our data

show a similar trend in rates of daily

excre-tion between cyclic AMP and phosphate

but with no clear linear correlation between

these two functions in the individual

for-mula-fed infants. Likewise, cyclic AMP

ex-cretion in breast-fed and formula-fed infants

is comparable even though it is known

that phosphate excretion is less in breast-fed infants.l4,hi However, a direct linear

correlation between phosphate and cyclic

-

AMP excretion due to changes in PTH

se-cretion would not necessarily be expected since at least in adults the maximum

phos-phaturic response to PTH is at a much

lower dose (10 mU/kg/mm) than the cyclic

AMP response which was still rising at the

highest dose employed at 80 mU/mm/kg. 3H cyclic AMP studies1#{176} in human adult T.LR

volunteers has shown that cyclic AMP is

: cleared by glomerular filtration at the same

rate as inulin but that the clearance exceeds

inulin clearance with a cyclic AMP/inulin

ratio of 1.5. This information implies that

two-thirds of the urinary cyclic AMP is

de-rived from the plasma circulation or GFR,

and one-third is released directly into the urine from the kidney. With this in mind, investigators have demonstrated a tendency

for increased cyclic AMP excretion in

hy-perparathyroid patients and decreased

ex-cretion in hypoparathyroid patients.8’17

(6)

TABLE II

COMPARISON OF NEWBORN AND ADULT URINARY

CYCLIC AMP

TABLE III

to 5.0 Nm of cyclic AMP/mg creatinine,

which is in the range of Day 1 infants, and the hyperparathyroid patients have excreted

as high as 12 Nm/mg creatinine with an

average of near 7 Nm/mg creatinine which

is comparable to the level in our 3 to 10

days of age infants.

The increasing cyclic AMP excretion

with age in infants is compatible with

in-creasing parathyroid activity and/or

in-creasing renal responsiveness to PTH but

this could be explained by other factors

than effects of phosphate intake and

cellu-lar maturation. Plasma cyclic AMP levels

and 3H cyclic AMP studies have not been

measured in infants so that the proportion of

urinary cyclic AMP contributed to by

clear-Cyclic AMP

Day 1 (10)

(mean ±

S.E.M.)

Day 3 (10)

(mean ±

S.E.M.)

Adult (14)

(mean ±

S.E.M.)

Nm/24 hr 53 ± 11 209 ±37

Nm/1.73M2 442±88 1,722±277 4,162±476 Nm/mgCr 2.37±0.41 6.93±0.96 3.62±0.41

ance and tubular excretion may be different

with maturation. There are other reasons

that can also be advanced for the increase

in the 24 hour cyclic AMP excretion. Both

glucagon and epinephrine have been noted

EFFEcrS OF PARATHYROID EXTRACT (PTE) INFUSION ON NEWBORN RENAL EXCRETION

OF PHOSPHATE AND CYCLIC AMP

.

Subject Period. Time.

(mm)

Phosphale Cyclic AMP

UVp mg/hr

-Cp % N/ Nm/mg

mi/mm TRP mm Cr

M.A. 1 150 0.05 0.13 99.6 0.09 3.92

A. Day 1

3,345gm

18 hours old 2

3

95

105

0.06

0.05

PTE 5 U/kg over next 60 mm

0.19 99.4 0.06 5.22

0.14 99.3 0.13 4.42

4 150 0.04 0.11 95.1 0.09 2.86

C.O. 1 45 0.04 0.11 99.3 0.07 3.48

B. Day 1

3,374gm

20hoursold

2

3

55

125

0.04

0.01

PTE 5 U/kg over next 60 mm

0.10 99.5 0.13 5.46

0.02 99.8 0.12 4.12

C.O. 1 105 2.32 0.52 76.3 0.08 6.35

B. Day3 2 50 3.35 0.75 75.4 0.16 8.84

3,374 gm

72hoursold 3 107 6.20

PTE 5 U/kg over next 60 mm

1.29 61.6 0.30 14.66 4 68 7.38 1.01 58.8 0.21 14.30

5 225 1.97 0.41 81.9 0.13 9.73

L.A. 1 166 2.05 0.54 89.4 0.35 11.60

C. Day 3

5,227gm

84 hours old 2

3

34

93

15.31

8.97

PTE 5 U/kg over next 60 mm

8.27 52.3 0.60 13.70

1.92 71.5 0.60 17.60

(7)

20

TABLE IV

EFFECTS OF PARATHYROID EXTRACT (PTE) INFUSION ON ADULT RENAL EXCRETION

OF PHOSPHATE AND CYCLIC AMP

.

Subject Period. Time.

(nun)

Phosphale Cyclic AMP

UVp

mg/hr

Cp % Nm/mm

mi/mm TRP Nm/mg Cr R.R. 1 2 65 60 7.9 28.1

8.16 97.1 2.9

11.15 91.0 6.3

2.87 5.63 3 4 5 60 60 60 52.0 64.0 4.0

PTE 5 U/kg over next 60 mmn

28.57 50.3 47.0

25.40 96.7 9.0 1.58 98.1 3.0

38.90 8.59 3.71 B.H. 1 2 60 60 4.03 13.20

2.24 97.9 5.6

7.34 94.1 3.1

3.42 2.46 3 4 5 6 43 22 74 66 7.45 30.19 30.65 16.81

PTE 5 U/kg over next 60 mm

5.31 93.0 10.9

16.77 88.0 46.4

15.00 86.8 7.4 8.35 93.6 3.9

14.51 37.85 8.63 5.46 A.B. 1 2 65 65 19.90 17.02

8.96 93.6 1.7

7.60 95.0 4.3

3.71 6.16 3 4 5 60 60 60 37.92 21.96 10.56

PTE 5 U/kg over next 60 mm

16.60 50.0 31.0

8.10 91.3 1.0

4.40 88.0 3.0

39.72

2.64

5.35

to cause increased urinary cyclic AMP

ex-cretion.18 Elevated cord blood and plasma

newborn glucagon-like activity have been

found in infantslO and could certainly play

a role in increased cyclic AMP excretion of

neonates. Even though newborn infants are

fully capable of producing

catechola-mines,20’2’ epinephrine is a weak stimulus to

cyclic AMP excretion.18 The GFR of

new-born infants with early cord clamping is

20.3 ± 1.2 ml/min/1.73 M2 (M ± S.E.M.)

at 1 to 12 hours of life compared to

33.0 ± 3.6 at 2 to 5 days of age.22 This

in-creasing GFR could in part explain

increas-ing cyclic AMP but would not explain adult levels at 1 day and high levels at 3 days of age.

Classical tetany of the newborn occurs

between 5 and 10 days of life and is more

prevalent in infants fed cow’s milk which

has the highest phosphorus content

(cow’s milk 96 mg/100 ml; Enfamil

for-mula 45 mg/100 ml; human milk 15 mg/

100 ml) and a low calcium-phosphorus

ratio (Cow’s milk 1.3; Enfamil 1.3; Human

2.2).1415 Insufficient PTH to induce

phos-phate diuresis to correct

hyperphosphate-mia or “transient hypoparathyroidism” was

postulated as early as 1936 to explain the

resultant hypocalcemia.23 One possible

mechanism involved is that milk feeding

with its phosphate load and subsequent low-ering of serum calcium is a physiologic

mechanism for challenging the

(8)

ITS. INFUSION

z

S.

0*81 0*134 *011.8

Fm. 6. Comparison of urinary cyclic AMP

ex-cretion in control urine to peak rise following

parathyroid extract infusion in the same patients

as Figure 5. The complete data are tabulated in Tables III and IV.

is an abrupt hyperphosphatemia with slight

hypocalcemia and a significant abrupt rise

in plasma parathyroid hormone within an

hour.’ Likewise, one possible interpreta-tion of our data showing increasing urinary

cyclic AMP/creatinine between the first

and third day of life is that there may be

increasing PTH secretion and/or

increas-ing renal responsiveness to PTH. Previously it had been shown that the fraction of fil-tered phosphate excreted by cow’s milk-fed

infants was higher than adults and did not

differ between normal infants or infants

with tetany leading McCrory, et aL25 to sug-gest inadequate compensatory

hyperpara-thyroidism rather than absolute hypopara-thyroidism. This is consistent with the

para-thyroid hyperplasia found in newborn

in-fants receiving cow’s milk.26’27 However,

there has been disagreement on the PTH

levels in newborn infants. PTH levels in

matched maternal-cord blood samples have

been shown both to be higher28 and lower in cord blood29 by different investigators.

Root, et al.29 finds the cord blood PTH

lower than maternal levels, and it remains lower in the first 72 hours of life.

Measure-ment of PTH levels beyond 72 hours of life

has not been reported. Kaplan26 noted the

parathyroid hyperplasia in the cow’s milk-fed infants between 3 to 10 days of life and

this hyperplasia was not present before 72

hours of life. Thus, it is uncertain whether

this hyperplasia means increasing PTH

se-cretion or is just an attempt to meet the

de-mands for PTH.

Connelly, et al.13 demonstrated a change

in the phosphaturic response to PTH with

aging by administering intramuscular PTH

on the first and third day of life. Since

PTH-induced phosphaturia is most likely

by renal cyclic AMP,8’9 our studies suggest that the maturational phosphaturic response to PTH is secondary to the maturational

cyclic AMP response to PTH. We were

unable to demonstrate a phosphaturic

response on the first day of life with

intra-venous PTH in our two patients but

Con-nellyl3 showed some responsiveness with

twice the dose intramuscularly with 24-hour

EJs.far.

c...

Al

urine collections. Further studies to

deter-mine when in infancy the cyclic AMP

re-sponse to PTH is comparable to adult

re-sponse are being conducted in our

labora-tory. McCrory, et al.25 has suggested by

studying phosphate excretion that

adult-like response occurs by 7 to 12 days of age. It is hypothesized that this diminished

re-sponsiveness may play a role along with

other factors such as low GFR in the

etiol-ogy of hyperphosphatemia and

hypocalce-mia of newborn infants.

Maturation of renal cortex adenyl cyclase in human neonates to explain the increasing

cyclic AMP responsiveness to PTH has not

been reported. There is a clinical entity

with a deficient renal cyclic AMP response

to PTH for which the underlying cellular

defect is unknown. Pseudohypoparathy-roidism is a clinical hypoparathyroid state

with normal PTH secretion and a

(9)

AMP ti1 ‘ Parathyroid

hormone-sensitive adenyl cyclase from the renal cor-tex of a patient with pseudohypoparathy-roidism has recently been demonstrated

making it unlikely that the primary defect

is either the parathyroid hormone receptor, or of the enzyme adenyl cyclase.3#{176} Broadus,

et al.18 have recently speculated that there

may be active renal tubular secretion of

cyclic AMP. Thus, a deficient transport sys-tem for this nucleotide needs to be searched

for in pseudohypoparathyroid patients and

similar approaches to explain diminished

responsiveness to PTH in the newborn

needs to be explored.

REFERENCES

1. Butcher, R. W., Robison, G. A., Hardinan, J. C.,

and Sutherland, E. W.: The role of cyclic AMP in hormone actions. Advances Enzym.

Regul., 6:357, 1968.

2. Butcher, R. W.: Role of cyclic AMP in hor-mone actions. New Eng. J. Med., 279:1378, 1968.

3. Butcher, R. W., and Sutherland, E. W.: Aden-osine 3’,5’-phosphate in biological materi-als. I. Purification and properties of cyclic 3’,5’-nucleotide phosphodiesterase and use

of this enzyme to characterize adenosine 3’,5’ phosphate in human urine. J. Biol. Chem., 237:1244, 1962.

4. Chase, L. R., and Aurbach, C. D.: Parathyroid function and the renal excretion of

3’,5’-adenylic acid. Proc. Nat. Acad. Sci. U.S.A.,

58:518, 1967.

5. Aurbach, C. D., Potts, J. T., Jr., Chase, L. R.,

and Melson, C. L.: Polypeptide hormones

and calcium metabolism. Ann. Intern. Med.,

70:1243, 1969.

6. Melson, C. L., Chase, L. R., and Aurbach,

C. D.: Parathyroid hormone-sensitive adenyl cyclase in isolated renal tubules. Endocrinol-ogy, 86:511, 1970.

7. Chase, L. R., and Aurbach, C. D.: The effect

of parathyroid hormone on the concentration of adenosine 3’,5’-monophosphate in skeletal tissue in vitro. J. Biol. Chem., 245:1520,

1970.

8. Kaminsky, N. I., Broadus, A. E., Hardman,

J. G., Jones, D. J., Jr., Ball, H., Sutherland, E. W., and Liddle, G. W.: Effects of

para-thyroid hormone on plasma and urinary adenosine 3’,S’-monophosphate in man. J.

Clin. Invest., 49:2387, 1970.

9. Ramussen, H., Pechet, M., and Past, D.: Ef-fect of dibutyryl cyclic adenosine 3’,5’-monophosphate, theophylline, and other

nucleotides upon calcium and phosphate metabolism. J. Clin. Invest., 47: 1843, 1968.

10. Kaneko, T., and Field, J. B. : A method for

determination of 3’,5’-cyclic adenosine mono-phosphate bases on adenosine triphosphate formation.

J.

Lab. Clin. Med., 74:682,

1969.

11. Chase, L. R., Melson, C. L., and Aurbach,

C. D. : Pseudohypoparathyroidism:

Defec-live excretion of 3’,5’-AMP in response to parathyroid hormone. J. Clin. Invest., 48: 1832, 1969.

12. Richmond, J. B., Kravitz, H., Segar, W., and Waisman, H. A. : Renal clearance of endoge-nous phosphate in infants and children. Proc. Soc. Exp. Biol. Med., 77:83, 1951. 13. Connelly, J. P., Crawford, J. D., and Watson,

J.: Studies of neonatal hyperphosphatemia.

PEDIATRICS, 30:425, 1962.

14. Gardner, L. I., MacLachlan, E. A., Pick, W.,

Terry, M. L., and Butler, A. M. : Etiologic

factors in tetany of newly born infants.

PE-DIATRICS, 5:228, 1950.

15. Citfieman, I. F., and Pincus, J. B.: Influence of diet on the occurrence of hyperphosphate-mia and hypocalcemia in the newborn in-fant. PEDIATRICS, 8:778, 1951.

16. Broadus, A. E., Kaminsky, N. I., Hardman,

J. C., Sutherland, E. W., and Liddle, C. W.: Kinetic parameters and renal clearances of plasma adenosine 3’,5’-monophosphate in man. J. Clin. Invest., 49:2222, 1970.

17. Taylor, A. L., Davis, B. B., Pawison, C.,

Josimovich, J. B., and Mintz, D. H.:

Fac-tors influencing the urinary excretion of 3’,5’-adenosine monophosphate in humans.

J. Clin. Endocr., 30:316, 1970.

18. Broadus, A. E., Kaminsky, N. I., Northcutt, R. C., Hardman, J. G., Sutherland, E. W., and Liddlle, C. W.: Effects of glucagon on adenosine 3’,S’-monophosphate and guano-sine 3’,5’-monophosphate in human plasma and urine. J. Clin. Invest., 49:2237, 1970. 19. Murthy, D. Y., and Colle, E.: Immunoassay of

glucagonlike activity in infants and children. (Abst.) Pediat. Res., 5:397, 1971.

20. Cheek, D. B., Malinek, M., and Farillon, J. M.:

Plasma adrenaline and noradrenaline in the neonatal period, and infants with respiratory distress syndrome and placental insufficiency.

PEDIATRICS, 41:374, 1963.

21. Creensburg, R. E., and Gardner, L. I.: The ex-cretion of free catecholamines by newborn infants. J. Clin. Endocr. Metab., 20:1207,

1960.

22. Oh, W., Oh, M. A., and Lind, J.: Renal func-tion and blood volume in newborn infant re-lated to placental transfusion. Acta Paediat. Scand., 56:197, 1966.

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tetany: Metabolic study. Amer. J. Dis. Child., 51:816, 1936.

24. Reiss, E., Canterbury, J. M., Bercovitz, M. A.,

and Kaplan, E. L.: The role of phosphate in

the secretion of parathyroid hormone in

man. J. Clin. Invest., 49:2146, 1970.

25. McCrory, W. W., Forman, C. W., McNamara,

H., and Barnett, H. L.: Renal excretion of

inorganic phosphate in newborn infants. J.

Clin. Invest., 31:357, 1952.

26. Kaplan, E.: Parathyroid gland in infancy.

Arch. Path., 34:1042, 1942.

27. Gardner, L. I.: Tetany and parathyroid

hyper-plasia in the newborn infant: Influence of

dietary phosphate load. PEDIATRICS, 9:534,

1952.

28. Lequin, R. M., Hackeng, W. H., and

Schop-man, W.: A radioimmunoassay for

parathy-roid hormone in man. II. Measurements of

parathyroid hormone concentrations in

hu-man plasma by means of a radioimmuno-assay for bovine hormone. Acta Endocrinol.,

63:655, 1970.

29. Root, A. W., Hawker, C. D., and Utiger, R.: Personal communications.

30. Marcus, R., Wilber, J. F., and Aurbach, C. D.:

Parathyroid hormone-sensitive adenyl

cy-clase from the renal cortex of a patient with

pseudohypoparathyroidism. J. Clin. Endocr.,

33:537, 1971.

Acknowledgment

We are deeply grateful to Miss Donna Stibel, R.N., head nurse, and the nursing staff of the Nur-sery at Mercy Hospital, Pittsburgh, Pennsylvania.

We wish to thank Dr. Frederic M. Kenny for his

helpful suggestions in reviewing this paper.

JOHN LOCKE (1632-1704) ON THE CHILD’S BED

In his Thoughts concerning Education, John

Locke, the philosopher-physician, gave a Mr.

Edward Clarke of Chipley, near Taunton,

Eng-land, detailed rules for bringing up his son.

Locke’s advice about Mr. Clarke’s son’s bed fol-lows:

Let his Bed be hard, and rather Quilts than

Feathers. Hard Lodging strengthens the Parts;

whereas being buried every Night in Feathers, melts

and dissolves the Body, is often the Cause of

Weak-ness, and the Fore-runner of an early Grave. And,

besides the Stone, which has often its Rise from this

warm Wrapping of the Reins; several other Indis-positions, and that which is the Root of them all, a tender weakly Constitution, is very much owing to

Downe-Becls. Besides, He that is used to hard

Lodg-ing at Home, will not miss his Sleep (where he has

most need of it) in his Travels abroad, for want of his soft Bed, and his Pillows laid in order. And

therefore, I think it would not be amiss, to make his Bed after different Fashions, sometimes lay his

Head higher, sometimes lower, that he may not feel

every little Change he must be sure to meet with,

who is not design’d to lie always in my young

Mas-ter’s Bed at home, and to have his Maid lay all

Things in print, and tuck him in warm. The great

Cordial of Nature is Sleep. He that misses that, will

suffer by it: And he is very fortunate, who can take

his Cordial only in his Mother’s fine Gilt Cup, and

not in a Wooden Dish. He that can sleep soundly,

takes the Cordial: And it matters not, whether it be on a soft Bed, or the hard Boards. ‘Tis Sleep only that is the Thing necessary.1

NOTED B T. E. C., Jn., M.D.

REFERENCE

1. Locke, J.: Thoughts concerning Education, ed.

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1972;50;14

Pediatrics

Louie G. Linarelli, John Bobik and Caroline Bobik

RESPONSIVENESS TO PARATHYROID HORMONE