Effect of LRH on Gonadotropin Secretion in Newborn Male Infants

Delitala, G.; Meloni, T; Masala, A.; Devilla, L.; Corti, Rachele

doi:10.1210/jcem-46-4-689

Cited by 16 publications

(7 citation statements)

References 10 publications

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“…Some boys with mild LH defi- T I M E minutes TIME m~n u t e s ciency may, however, have been included since this is frequently associated with incomplete testicular descent (6). The concentrations of FSH in the present study were in agreement with earlier reports whereas the LH levels were higher, presumably due to methodological differences (1,14,15). The response pattern of the gonadotropins to GnRH was similar to that described in earlier studies ( 1, 14).…”

Section: Discussionsupporting

confidence: 91%

Responsiveness of the Pituitary-Testicular Axis to Gonadotropin-releasing Hormone and Chorionic Gonadotropin during the First Week of Life

et al. 1984

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ABSTRACT. Qualitative changes are known to occur in testicular steroidogenesis at birth as the testosterone peak is reached without significant elevation of basal luteinizing hormone in the 2nd wk of life. This study was designed to evaluate testicular activity prior to these changes. Pituitary-testicular function was studied by measuring serum gonadotropins and steroids after stimulation by gonadotropin-releasing hormone (GnRH) (one intravenous injection) and human chorionic gonadotropin (hCG) (three intramuscular injections). The subjects had minor genital anomalies; their ages ranged from 2 to 6 days. All had a strong luteinizing hormone response and a weaker follicle-stimulating hormone response to GnRH stimulation. hCG induced significant increases in serum pregnenolone, 17-hydroxyprogesterone, androstenedione, testosterone, and dihydrotestosterone. Serum estradiol and estrone did not change, and progesterone decreased. The results clearly show that the pituitary-testicular axis is functional neonatally. The responsiveness of the testis to hCG supports the assumption that the postnatal decrease of testicular steroids is due to the simultaneous disappearance of hCG from the circulation. Ez, estradiolIn male infants, the relatively high concentrations of serum testosterone found on the 1st postnatal day decrease rapidly to a low level which is maintained for about 1 wk, after which a transient activation of the hypothalamic-pituitary-testicular axis Received November 28, 1983; accepted March 23, 1984 takes place (4, 12, 1 3, 16). During the period of relative testicular quiescence on days 3 to 6 after birth, stimulation by GnRH evokes significant response in serum LH concentrations (14). It has not been knbwn to date whether the testis could respond to LH or hCG stimulation in this period. The aim of this study was to test this as such information would be of value in understanding the regulation of testicular function. As such studies cannot be made in normal human newborns we chose those with only minor genital anomalies as subjects. They were given a GnRH test followed by a hCG test. MATERIALS AND METHODS Subjects.Our series consisted of 16 full-term newborn male infants with minor genital abnormalities. They were 2.25 to 6.0 days old at the beginning of the testing. Twelve had incomplete testicular descent; nine unilaterally (four testes were not palpable) and three bilaterally (all inguinal). Only one infant had a testis still not palpable at the age of 12 months but at surgery, it was found to be of normal size and consistency. Three of the other infants needed an orchidopexy at the age of 1 yr. Two infants had surgically insignificant glandular hypospadias and two had a penis shorter than mean -2SD for gestational age (2). The Ethical Committee of the Hospital approved this study, and an informed consent was obtained from all parents.Tests. To the release of the pituitary gonadotropins, GnRH (Relefact, Hoechst AG, F. R. G.), 3.5 pg/kg was injected intravenously during 1 min between 0830 and 1100. One-...

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Section: Discussionsupporting

confidence: 91%

Responsiveness of the Pituitary-Testicular Axis to Gonadotropin-releasing Hormone and Chorionic Gonadotropin during the First Week of Life

et al. 1984

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“…The brisk rise of B-LH in males from the nadir on day 4 probably represents active endogenous B-LH secretion and thus suggests activity of the hypothalamic-hypophyseal axis. This concept is further supported by the fact that newborn males have responded to exogenous LHRH with a pubertal pattern of LH secretion (16).…”

Section: Lh-hcg (B-lh)mentioning

confidence: 91%

Dynamics of Bioactive Luteinizing Hormone-Human Chorionic Gonadotropin during the First 7 Days of Life

et al. 1988

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ABSTRACT. Serum luteinizing hormone-human chorionic gonadotropin bioactivity (B-LH) was measured daily in seven male and four female full-term newborns during the first 7 days of life. The B-LH levels were elevated in both sexes during the 1st day of life; subsequently, values decreased in both sexes. In males, they reached a nadir on the 4th day of life. A gradual secondary rise was then observed with B-LH levels on the 7th day significantly higher than on day 4 ( p < 0.025). By contrast, the B-LH levels in the females continued a gradual decline to levels significantly lower on day 7 as compared to day 4 ( p c 0.05). To determine whether pulsatile B-LH secretion occurs in newborns, serum concentrations were measured every 20 min for 2 h in eight male and seven female fullterm neonates on the 7th day of life. Pulsatile secretion of B-LH was detected in six males and six females. This study demonstrates that pulsatility of gonadotropin secretion is characteristic of neonates as early as 7 days of life and that there is a dichotomy between the levels of B-LH in males and females; levels in females decline progressively from day 1 through 7, whereas in males, a nadir is reached on day 4 with a secondary rise developing thereafter. This male sex-specific rise is presumably the drive responsible for the characteristic postnatal increase in testosterone which peaks at 1 to 2 months of age. (Pediatr Res 23: 530-533,1988) Abbreviations LH, luteinizing hormone hCG, human chorionic gonadotropin B-LH, bioactive luteinizing hormone RICT assay, rat interstitial cell testosterone assay 2nd-IRP, second international reference preparation hMG, human menopausal gonadotropin FSH, follicle-stimulating hormone LHRH, luteinizing hormone-releasing hormone so that by the end of the 1st wk the levels have diminished to a nadir, at which they are comparable to the levels characteristic of normal childhood. A second and longer sustained rise of plasma testosterone commences in the 2nd wk of life. Testosterone concentrations rise progressively to plateau during the 2nd month of life at levels that are not seen again until puberty (2, 3). This biphasic course of plasma testosterone concentration presumably relates to changes in testicular secretion and has been correlated with transient elevations in plasma LH concentrations as measured by immunoassay (4).The present study was undertaken to describe the changes in plasma gonadotropins of the LH-hCG class as measured by bioassay during the first 7 days of life. It was also designed to show whether newborns display pulsatility of gonadotropin secretion of the type seen in normal puberty (5). Finally, it afforded an opportunity to contrast the pattern of bioactive gonadotropins in the male with that in female neonates. MATERIALS AND METHODSClinical studies. Studies were carried out in two groups of neonates according to protocols approved by the Human Studies Committee of the Universidad del Valle. The first group consisted of seven male and four female newborns. All of the infants were ...

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“…The results confirmed previous studies of Meijs-Roelofs and Kramer [1979] that a feedback interaction between the ovary and the hypothalamo-adenohypophysial system may be established during the early days of life in the rat. It has reported that so-called castration cells occur due to the elevated secretion of hypothalamic LHRH triggered by gonadectomy [Arimura et al, 1976], Delitala et al [1978] reported that LH and FSH rose significantly in male newborn babies after LHRH administration. This indicates that the receptor responses to LHRH in the anterior pituitary gland are functional at birth.…”

Section: Arai and Masudamentioning

confidence: 99%

“…Nakai et al [1972] reported that bilateral castration of male rat fetuses on the 21st day of gestation increased the number of PASpositive cells. It is evident that castration cells were induced by an elevation in hypothalamic LHRH after gonadectomy [Arimura et al, 1976], Delitala et al [1978] reported that gonadotrophins significantly rose in human newborn babies (aged 4-6 h) after synthetic LHRH administration. This demonstrates that the sensitivity of the pituitary to LHRH and a pubertal type LH response was already established during the early hours of life in the newborn infant.…”

Section: Introductionmentioning

confidence: 99%

Effects of Neonatal Ovariectomy on the Ultrastructure of Gonadotrophs in Female Rats

Shiino¹,

Yamauchi²

1983

Cells Tissues Organs

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In order to investigate if castration cells or hypertrophic gonadotrophs are induced by ovariectomy at birth, neonatal female rats were ovariectomized within 12 h after birth and the pituitary cells were examined when the rats were 15 days of age by means of immunocytochemistry and electron microscopy. Hypertrophic gonadotrophs were present in the anterior pituitary glands of these young rats. However, when estradiol was injected on alternate days, beginning on the 5th day after birth, this castration response in the pituitary was markedly suppressed. This morphological evidence confirms physiological results previously reported that a feedback interaction between the ovary and the hypothalamo-adenohypophysial system is functional in the early days of life.

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Effect of LRH on Gonadotropin Secretion in Newborn Male Infants

Cited by 16 publications

References 10 publications

Responsiveness of the Pituitary-Testicular Axis to Gonadotropin-releasing Hormone and Chorionic Gonadotropin during the First Week of Life

Responsiveness of the Pituitary-Testicular Axis to Gonadotropin-releasing Hormone and Chorionic Gonadotropin during the First Week of Life

Dynamics of Bioactive Luteinizing Hormone-Human Chorionic Gonadotropin during the First 7 Days of Life

Effects of Neonatal Ovariectomy on the Ultrastructure of Gonadotrophs in Female Rats

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