No abstract

The fine structure of the interstitial gland of the rat ovary was studied at estrus and on Days 4, 6, 10, 14 and 18 of pregnancy. At estrus, ovarian interstitial cells have small nuceli with dense irregular clumps of heterochromatin. Mitochondria are small and rod-shaped and have predominantely lamellar cristae. Numerous osmiophilic lipid droplets are present. At Days 4 and 6, nuclear heterochromatin is reduced, and nucleoli are larger and complex. Mitochondria are enlarged and often bizarre-shaped and have tubular cristae. Golgi and smooth endoplasmic reticulum are more conspicuous. At Day 10, prominent ultrastructural features include nuclei with conspicuous heterochromatin, smaller mitochondria with both lamellar and tubular cristae, numerous ribosomes and lipid droplets with decreased osmiophilia. At Days 14 and 18, nuclei have increased heterochromatin, mitochondria are small and have lamellated cristae and an increase in the size and number of lipid droplets occurs. These observations suggest that steroidogenic activity of interstitial cells is highest during the first half of pregnancy and regresses during the last half. It is suggested that the interstitial gland is an important ovarian source of pregnancy hormone(s) during the first half of gestation and that LH may modulate steroidogenic activity is this ovarian component.

Pregnant Sprague-Dawley r a t s were laparotomized on days 8-10 and sham-operated (S) o r subjected t o b i l a t e r a l section of the pelvic parasympathetic nerves (pelvic neurectomy ( P N ) ) . Both S and PN animals were allowed t o go t o term and the time o f delivery was recorded E i g h t of ten S animals delivered on the afternoon of day 22 and two delivered on the morning of day 23. Pelvic neurectomy blocked partur i t i o n in f i v e r a t s autopsied on day 24, and f i v e r a t s autopsied on day 26. On these days the PN animals had full-term fetuses; l i v e on day 24, b u t dead on day 26. In a second study, t h e f i n e s t r u c t u r e of t h e myometrium of S and PN pregnant r a t s was examined during the part u r i e n t period f o r the presence of gap junctions. Gap junctions were present between myometrial smooth muscle c e l l s o f the S group during delivery and i n the PN group on days 23, 24, and 25, in the absence of delivery. number of gap junctions on day 23 i n the PN animals. There was no difference i n the length of gap junctions i n the d i f f e r e n t groups. These observations indicate t h a t t h e parturition block c h a r a c t e r i s t i c of PN animals i s not a t t r i b u t a b l e t o the f a i l u r e of gap junction formation between smooth muscle c e l l s . Apparently, the nervi erigentes p a r t i c i p a t e i n the orchestration of events terminating in p a r t u r i t i o n , b u t t h e i r specific role remains an enigma.There was a s i g n i f i c a n t increase ( p c 0.05) i n the Several authors have reported t h a t b i l a t e r a l section of t h e pelvic parasympathetic nerves (nervi erigentes) in the r a t block parturition (Carlson and DeFeo, '65; Spies e t a l . , '71; Lawrence e t a l . , '78; Louis e t a l . , '78).The mechanism whereby section of the pelvic parasympathetic nerves (pelvic neurectomy ( P N ) ) blocks parturition i s poorly understood.Recently i t was reported t h a t formation of gap junctions i n t h e myometrium immediately prior t o delivery i s necessary f o r parturition t o occur (Garfield 105

Rat ovarian perifollicular contractile tissue was examined at specified intervals prior to ovulation to determine the type, relative number, and length of cellular junctions. Rat ovaries were taken for electron-microscopic observation at 1500 h on the afternoon of proestrus (proestrus 0-h group), at 2000 h (proestrus 5 h group), at 0100 h (proestrus 10-h group) and at 1600 h on the afternoon of diestrus I. Close junctions, intermediate junctions, and gap junctions were counted and measured. Then number of gap junctions/1,000 micrometers of membrane and the number of intermediate junctions/1,000 micrometers of membrane was significantly higher in the proestrus 10 h groups as compared to the other groups. There was no difference in the number of close junctions during the periods studied. Also the length of all junctions was similar in all groups. These morphological findings are discussed in the context of contractile role for perifollicular tissue in the ovulatory process.

The structure of the human ovarian ligament was studied with light and electron microscopy, with emphasis on neural components. The ligament is primarily composed of smooth muscle arranged in an outer oblique and an inner longitudinal layer. The smooth muscle cells are connected by two types of intercellular junctional complexes, close contacts and intermediate junctions. The intercellular junctions may serve to coordinate smooth muscle activity and synchronize contractions of the ligament. Nerves are abundant and accompany the vascular supply. Specialized encapsulated neural structures previously reported were not observed. Acetylcholinesterase-positive nerves are more numerous than adrenergic nerves. Both types of nerves are associated with vascular smooth muscle. We conclude that these nerves either traverse the ligament or terminate in the ligament and are vasomotor.