R. M. Fraps

On the function of the Ruptured Ovarian Follicle of the Domestic Fowl

Summary Removal of the ruptured ovarian follicle or of this follicle together with the oldest maturing follicle of the hen at the time when the egg taking its origin from the ruptured follicle was in the oviduct almost invariably resulted in the holding of the egg beyond the expected time of lay. Most eggs were held from 1 to 7 days. Removal of other parts of the ovary at comparable times, without simultaneously removing the most recently ruptured follicle, practically never resulted in comparable holding of the oviducal egg. The ruptured follicle of the hen is believed therefore to be an important factor in determining the time of lay of the egg formed from its previously contained ovum.

Time Required for Induction of Ovulation Following Intravenous Injection of Hormone Preparations in Fowl

Summary The time at which ovulation occurs following intravenous injection of appropriate hormone preparations into pretreated and normally laying (non-pretreated) hens has been determined. The interval in pretreated hens averaging more than 2 ovulations per hen at time of autopsy was 6.8 hours, range 6.1-7.2 hours. Ninety percent of all normally laying hens (69) ovulated from 6.5 to 8.5 hours following ovulatory injection, the remaining 10% of injected hens requiring up to 9.6 hours for ovulation. The non-pretreated hens were injected with 4 different hormone preparations administered at differing dosage levels and at times calculated to effect ovulation of follicles at varying degrees of prematurity. The minimal ovulatory interval recorded for pretreated hens was 6.1 hours, for non-pretreated hens, 6.5 hours.

Blockade of Gonadotrophin Release for Ovulation in the Hen following Stimulation with Stainless Steel Electrodes

Summary Bilateral stimulation with bipolar stainless steel electrodes was applied for 10 minutes in a selected region of the median eminence of the hen, 14 hours before expected normal ovulation of the C1 follicle. In 28 of 52 hens, ovulation was delayed by 3 to 10 hours or more. The delays in ovulation were shown to arise out of delays in or blockade of the release of ovulation-inducing hormone (OIH). The effects of stimulation on delay of OIH release may extend over a period of 12 to 14 hours. Stimulation with platinum electrodes or placement of steel or platinum electrodes without passage of current failed to delay OIH release. The prolonged effects of stimulation with stainless steel electrodes are consistent with the conclusion of Everett and Radford that electrolytically deposited iron may act irritatively long after application of the stimulatory current.

Delaying Action of Gonadotropins on Ovulation in the Hen.

Summary Antiadrenergic, anticholinergic or central depressant drugs suppress or delay, in varying proportions, ovulation of the second or C2 follicle of the hens sequence following their administration some 18-20 hours before normally expected ovulation. In an attempt to counteract these effects, a whole anterior pituitary (AP) preparation from cocks was injected intramuscularly shortly before injection of several of the drugs. The incidence of suppressed ovulations was increased by the AP preparation, and increased proportions of suppressed ovulations exhibited C1 lapses, i.e., the normally expected C2 ovulation was delayed only until the hour of typical C1 ovulation on the day following its suppression. Intramuscularly injected 18-19 hours before expected C2 ovulation, the AP preparation alone suppressed ovulation in most hens, with a high proportion of C1 lapses. Under similar conditions, luteinizing hormone (LH) or follicle stimulating hormone (FSH) from cock pituitaries suppressed ovulation in some hens. Administration of 0.02 mg LH + 2 mg FSH/hen suppressed ovulation in 93% of injected birds, and all of these exhibited the C1 lapse. Progesterone injected at about the hour of normally expected release of ovu-lation-inducing hormone (OIH) effected ovulation in most hens previously treated with the AP preparation, indicating that gonadotro-phin-induced lapses resulted from a transient “blockade” of the nervous mechanism controlling OIH release. Since estrogens similarly “block” C2 ovulation in the hen, the gonadotrophin-induced delay may be attributed to increased levels of circulating estrogen. Enforced estrogen production may however be associated also with reduced or delayed output of the hormone believed to excite the nervous component of the OIH release mechanism.

Induced Ovipositions in Relation to Age of Oviducal Egg in the Domestic Hen

Summary Hens carrying oviducal eggs were injected with 0.30 unit of Pitressin at times equivalent to 1, 5, 9, 15, and 19 hours of time passed by the egz in the uterus. The percentages of birds laying prematurely were respectively 14, 32, 50, 51, and 56. Removal of the ruptured iollicle shortly aitcr reached its almost maximum size. The reovulation did not alter the response at the 19th hour in the uterus stage. The begining of the plateauof the response curve approximately coiilcided with the time at which theoviducal egg hecarne fully plumped, i.e. reached its almost maximum size. The response curve was interpreted as the expression of a change in the mechanical relationsbetween the uterus and the contained egg, rather than a change in intrinsic sensitivitydue to the action of the ruptured follicle.

No androgen in corn pollen.

Summary Extraction of corn pollen and assay of the extracts according to procedures commonly used on animal materials failed to yield any evidence of androgenic substances.