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Adrenocorticotropin (ACTH), α-melanocyte-stimulating hormone (α-MSH) and desacetyl-α-MSH (des-α-MSH) concentrations were evaluated in 4 embryos and 18 fetal pituitaries collected after spontaneous (n = 9) and prostaglandin-induced abortion (n = 9) at 13–25 weeks of gestation. The peptides were measured by radioimmunoassays after a high-performance liquid chromatographic separation of the homogenates. In both embryonic and fetal pituitaries, des-α-MSH concentrations were 2–4 times higher than those of α-MSH and 1- to 50-fold increased in comparison to those of ACTH. Either melanotropin showed the highest pituitary content in the first part of the second trimester, while the ACTH content remained constant. In the oldest fetuses (over 20th week), the pituitaries collected after prostaglandin-induced abortion showed markedly increased values of both des-α-MSH and α-MSH in comparison to samples collected after spontaneous abortion. In conclusion, des-α-MSH, the typical melanotropic hormone of fetal pituitary, undergoes important changes during development. Des-α-MSH seems to be the end product of proopiomelanocortin cleavage and its pituitary content increases in concomitance with the fetal adrenal sprout. Moreover, these data indicate that the intermediate pituitary lobe could be activated by the stress of labor after the 20th week of pregnancy.

ABSTRACT. A total of 21 human fetal pituitaries was parturition (4-6). Moreover, a significant secretion of P-EP occollected from spontaneous abortions (11 cases) or pros-curs in the neonatal period, both in vaginally delivered babies taglandin (PG)-induced abortions at the second trimester. and in those born by cesarean section in the absence of labor, Pituitaries were homogenized, fractionated by HPLC, and suggesting that neonatal P-EP secretion is an important factor of the fractions were tested by specific RIA for a-endorphin extrauterine adaptation (7,8). Fetal pituitary contains ACTH (9) (EP) (P-EP 1-16), y-EP (P-EP 1-17), P-EP (P-EP 1-31), and P-EP from the early stages of development (10-12), and and their a-N-acetylated derivatives. In the fetal pituitaries secretion has been documented in vitro after the 20th wk of collected after spontaneous abortion, the contents of a-EP pregnancy (1 3). However, the biologic activity of 0-EP may (23.4 f 7.5 pmol/mg prot, mean f SE) and y-EP (28.9 f change during fetal life because P-EP represents the precursor for 9.7) were similar to those of P-EP (28.6 2 7.4). Both P-smaller peptides, such as a-and y-endorphins with psychostim-EP/a-EP (1.2 f 0.3) and P-EP/y-EP (1.1 f 0.3) ratios ulant and neuroleptic-like profiles, respectively (14, 15). Moreapproached unity. Although 35.7 and 30.2% of a-EP and over, P-EP may be acetylated at its N-terminus, losing its opioid y-EP were acetylated, acetyl-P-EP was only 8.4% of the properties (16). In some mammals, the a-N-acetyltransferase total P-EP immnoreactivity. In the five cases of PG-induced activity is lacking in anterior pituitary and is typical of the abortion that were more than 20 wk of pregnancy, the neurointermediate lobe (17,18). This is present in the human pituitary content of P-EP (75.9 f 21.2) and y-EP (26.2 f fetus but involutes after birth and is normally absent as an 7.5) were significantly higher than in samples collected anatomically differentiated structure in the adult human pituiafter spontaneous abortion (13.3 f 8.2 and 5.9 f 1.8, tary (19). ~i~~~~~. ~~~~l pituitaries were immediately after the 17th wk pregnancy, no differences were seen abortion in 1 1 cases (five cases between the 13th and the 17th paring PG-induced and spontaneous abortions. 'IXese data wk and six between the 20th and the 25th wk of pregnancy). demonstrate that in the fetal pituitary: 1 ) P-EP retains its Spontaneous abortions were due to oligohydramnios (five cases) opioid biologic activity because only a small percentage is 0, to cervical incompetence (4). In two other cases, hysterotomy acet~lated, 2) shortened endorphins are quantitatively as for multiple myomas was performed at the 13th and 14th wk of important as @-EP, and 3) after mid-gestation, the fetal pregnan,y. Then 10 additional pituitaries were collected after proopiomelanocortin synthesis or processing may be sen-p~-induced abortion during the second trimester (five cases sitive to endocrine or environmental stimuli. (Pediatr Res between the 14th and 17th wk and the oth...

This study evaluates the presence of proopiomelanocortin (POMC)-related peptides in four embryos and eight fetal pituitaries starting from 5 to 25 weeks of pregnancy. Moreover, fetal membranes (amnion and chorion) were also investigated. Freshly collected samples were boiled in acetic acid to destroy enzymes, homogenized and submitted to high performance liquid chromatography (linear gradient from 25 to 40% acetonitrile in 0.01 M HCI, in 15', 1.5 ml/min). The collected fractions were tested for the presence of beta-lipotrophin (beta-LPH), beta-endorphin(beta-EP), gamma-endorphin(gamma-EP) through RIAs. beta-EP and beta-LPH were detected from 7 weeks of pregnancy while gamma-EP appeared later. Only the cephalic portion of the embryos contained the peptides where beta-LPH predominates while no immunoreactivity was detected in the rostral one. In the fetal pituitary there is a progressive increase of gamma-EP according to the gestational age and both beta-EP and beta-LPH showed a trend toward constancy in the 15-25 week range. Amnion and chorion contain a significant amount of the three peptides. Their ontogenesis starts earlier than in the embryo; beta-LPH or beta-EP were detected at 5 weeks of pregnancy. In both tissues beta-EP was higher in the first than in the second trimester. These data demonstrate a different pattern of POMC ontogeny and processing between the conceptus and his environment. This suggests that the POMC-related opiod system of the fetus and of fetal adnexes are independent of each other, possibly subserving to different functions.