Ovarian control of pituitary hormone secretion in early human pregnancy.
To determine the influence of ovarian relaxin on the secretion of pituitary GH and PRL in vivo, we evaluated circulating serum hormone levels in 17 pregnant patients with functional corpora lutea (group I) and compared them to levels in 10 patients with premature ovarian failure (POF; group II) who became pregnant with egg donation and did not have corpora lutea. Group II patients had exogenous hormonal support. Serum relaxin (RLX), GH, PRL, estradiol (E2), and progesterone levels were measured weekly by RIA from weeks 4-8 of pregnancy. Analysis of variance and covariance were used to determine hormonal relationships. Serum RLX was present in the natural pregnancy group, with a mean of 1.94 micrograms/L over the study period. Serum RLX was undetectable in the POF patients (less than 0.16 micrograms/L). No significant difference in PRL or progesterone levels between the two groups was noted. E2 levels showed an upward trend in both groups with time and were significantly higher in patients of the POF group than in group I women (P = 0.001). GH levels were significantly higher in the natural cycle patients (P = 0.02) despite lower E2 levels. These data provide additional support for the concept that RLX production in early pregnancy originates from the corpus luteum. They suggest that a luteal product, probably RLX, stimulates GH secretion in early pregnancy. This is a previously undescribed role for RLX in pituitary physiology during human pregnancy.
Emmi
A M
AM
Department of Obstetrics and Gynecology, and Preventive Medicine and Community Health, University of Medicine and Dentistry-New Jersey Medical School, Newark 07103.
Skurnick
J
J
Goldsmith
L T
LT
Gagliardi
C L
CL
Schmidt
C L
CL
Kleinberg
D
D
Weiss
G
G
D000328:Adult; D003338:Corpus Luteum / Q000502:physiology; D005260:Female; D012739:Gonadal Steroid Hormones / Q000378:metabolism; D006801:Humans; D010049:Ovarian Diseases / Q000378:metabolism; D010053:Ovary / Q000502:physiology*; D010907:Pituitary Hormones / Q000378:metabolism*; D011247:Pregnancy / Q000378:metabolism*; D011261:Pregnancy Trimester, First; D012065:Relaxin / Q000378:metabolism
D012739:Gonadal Steroid Hormones; D010907:Pituitary Hormones; D012065:Relaxin