Duration of Chorionic Gonadotropin Production by the Placenta of the Rhesus Monkey

Abstract

Concentrations of macaque chorionic gonadotropin (mCG) in placenta, blood and urine of rhesus monkeys have been measured by both radioimmunoassay and bioassay throughout gestation. mCG was easily detected and quantified in these specimens for a brief period in early pregnancy, but was not detectable between the 40th day of pregnancy and term in placental extracts, serum, or 40-fold urine concentrates. The apparent absence of mCG after the 40th day of pregnancy makes these macaques a valuable model for pregnancy research, where the absence of chorionic gonadotropin is experimentally desirable. Unlike women and some higher primates, the functional status of the fetal, placental and maternal endocrine compartments of macaques can be studied in the absence of circulating chorionic gonadotropin during mid and late gestation.

Detection of Macaque Chorionic Gonadotropin in the Placenta of the Cynomolgus Monkey (Macaca Fascicularis)

“…The present results clearly indicate that mCG was detectable in placental extracts only at the beginning of gestation period also in the cynomolgus monkey as was demonstrated in the rhesus monkey by Hodgen et al (1975). The extracts from the 4th-and 5th-week placentas were positive for mCG, inducing not only uterine and ovarian weight gains but also opening of the vagina, corpus luteum or follicle formations and hydrometra, in immature mice.…”

“…At the same time, he determined mCG in the placenta with a maximum concentration at term (Hobson, 1972b). In contrast to Hobson's findings, Hodgen et al (1975) demonstrated that mCG could not be detected during the middle or late stage of gestation in the placenta, serum or urine of the rhesus monkey. The present investigation was performed to examine the placenta of the cynomolgus monkey for mCG at various stages of gestation by a bioassay method.…”

The Similarity of Chorionic Gonadotrophin and Its Subunits in Term Placentae from Man, Apes, Old and New World Monkeys and a Prosimian

“…CG has been found in the term placenta of the chimpanzee, the rhesus monkey and the common mar moset [Hobson, 1972;Hobson and Wide, 1972]. However, others have claimed that the placenta of the rhesus monkey is devoid of CG by the 7th week of preg nancy [Hodgen et al, 1975], and that of the baboon after the 11th week [Tullner, 1967]. It has been stated that 'only apes and man make chorionic gonado trophins throughout gestation' [Chen and Hodgen, 1976], implying that term placentae of monkeys and prosimians do not contain CG.…”

An appraisal of the mouse uterine weight assay for the bioassay of chorionic gonadotrophin in the macaque term placenta

“…These results emphasize the difference in target organ sensitivity of the YOK-ddy and Schofield mice. The negative results obtained by Hodgen et al (1975) with extracts of rhesus monkey placentae after the 10th week of gestation are difficult to assess. Their bioassay, similar to the one used in the present investigation, was a modification of the Levin & Tyndale (1937) method with a claimed sensitivity of 01 i.u.…”