Absence of Light and the Reproductive Cycle in the Guinea Pig

Dempsey, Edward W.; Myers, Hugh I.; Young, William C.; Jennison, David B.

doi:10.1152/ajplegacy.1934.109.2.307

Cited by 27 publications

(7 citation statements)

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“…Robertson & Falconer (1961) observed abrupt rises in PB1271 levels and in the rate of release of 131I from the thyroid gland coincident with oestrus and ovulation in the ewe. The ovarian cycle of the hamster may not be, and the cycle of the guinea-pig is not, influenced by environmental light (Dempsey, Myers, Young & Dennison, 1934) and in the present study and an earlier one (Brown-Grant, 1962b) increases in thyroid gland activity that may be related to ovulation were observed. The human ovulates spontaneously with no known influence of light being involved; previous studies have failed to establish any significant variation in thyroid activity during the menstrual cycle although evidence suggestive of an increase at mid-cycle have been reported (see, for instance, Pochin, 1952 and references in Brown-Grant, 1956).…”

Section: Discussionsupporting

confidence: 62%

The relationship between ovulation and the changes in thyroid gland activity that occur during the oestrous cycle in rats, mice and hamsters

Brown-Grant¹

1966

The Journal of Physiology

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SUMMARY1. When ovulation is prevented by the injection of pentobarbitone on the day of pro-oestrus in female rats, the expected increases in thyroidserum concentration ratio (T/S ratio) for 131I and in the uptake of 113I by the thyroid on the day of oestrus do not occur.2. Ovulation induced by human chorionic gonadotrophin or ovine luteinizing hormone in rats treated with pentobarbitone at pro-oestrus is not associated with an increase in T/S ratio or 131I uptake at oestrus.3. These results support the view that it is the neuro-endocrine changes at the hypothalamic or pituitary level that lead to ovulation rather than changes in the pattern of ovarian steroid secretion before or at ovulation that are responsible for the increased thyroid activity at oestrus in the female rat.4. Experimental evidence of an increase in thyroid activity after ovulation in mice and hamsters also supports this view.

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Section: Discussionsupporting

confidence: 62%

The relationship between ovulation and the changes in thyroid gland activity that occur during the oestrous cycle in rats, mice and hamsters

Brown-Grant¹

1966

The Journal of Physiology

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“…Our own attempts to use this technique for determining the right time to pair guinea-pigs were unsuccessful. Unsatisfactory results were also obtained by attempting to time ovulation by means of change of daylight (Dempsey, Myers, Young & Jennison, 1934;Donovan & Lockhart, 1972) or by inducing oestrus through administration of hormones (Dempsey, Hertz & Young, 1936;Ford & Young, 1951). The most common method presently in use takes advantage of the occurrence of oestrus post partum but it suffers from being slow and not completely reliable.…”

Section: Discussionmentioning

confidence: 99%

Vaginal impedance measurement used for mating in the guinea-pig

Bartoš

Sedláček

1977

Lab Anim

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57Summary A method for determining the phase of the oestrous cycle by measuring the electrical impedance of the vaginal mucous membrane was examined in the guinea-pig. The apparatus consisted of silver ring electrodes attached to a plastic rod and connected to a transistor indicator.A cyclic increase in impedance was found, and significantly higher values were recorded during the phase of increase (proestrus) than at other times of the cycle. By determining this peak the right time for pairing can be chosen. Conversely, the disappearance of this cyclic culmination in impedance pointed to early pregnancy with a high degree of reliability.For some ontogenetic studies it is essential to have precise information on foetal age and for this reason it is important to be able to determine the day of mating. In the guinea-pig the use of vaginal cytology was first reported by Stockard & Papanicolau (1917); later references to this technique include those of Young, Myers & Dempsey (1933) and Hermreck & Greenwald (1964). Our own attempts to use this technique for determining the right time to pair guinea-pigs were unsuccessful. Unsatisfactory results were also obtained by attempting to time ovulation by means of change of daylight (Dempsey, Myers, Young & Jennison, 1934;Donovan & Lockhart, 1972) or by inducing oestrus through administration of hormones (Dempsey, Hertz & Young, 1936;Ford & Young, 1951). The most common method presently in use takes advantage of the occurrence of oestrus post partum but it suffers from being slow and not completely reliable. So far the best results have been obtained by measuring changes in electrical impedance of the vaginal mucous membrane, as described in the rat (Bartos, 1977). Our experience with this technique in the guinea-pig is described below. Materials and methodsThe electrical impedance of the vaginal mucous membrane (Elv.m.m.) was measured as described for the rat (Bartos, 1977), except that the distance between the ring electrod.:s was 6 mm.A total of 30 female guinea-pigs, aged I year, was used for the basic measurements, which were made once daily at about 0900 over 61 days. In the case of the ontogenetic experiment described by Sedlatek (1976) at proestrus was 3027 :1-170 n compared with a mean of 1041 ± 9 n for the other phases of the cycle; the difference is statistically significant (P

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“…Thus the guinea-pig is little affected by changes in the amount of light (Dempsey et al 1934) and the same is the case with the spermophile (Johnson & Gann, 1933). Thus the guinea-pig is little affected by changes in the amount of light (Dempsey et al 1934) and the same is the case with the spermophile (Johnson & Gann, 1933).…”

Section: Experiments With Light and Ultra-violet Irradiationmentioning

confidence: 94%

Exteroceptive Factors in Sexual Periodicity

Marshall

1942

Biological Reviews

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Summary 1. In all mammals and probably in all vertebrates there is an internal endocrine sexual rhythm with alternating periods of rest and activity. This cycle is usually adjusted to external seasonal changes and with some marked exceptions spring is the period of greatest sexual activity, but there is much specific variation and among ruminating mammals breeding is generally in autumn. 2. Among tropical and subtropical animals breeding is not nearly so restricted to definite seasons, and there is evidence that ecological factors play a part in its recurrence. 3. In individual animals which are made to cross the equator there may be two seasons of sexual activity in the year and the times of breeding are eventually reversed though the original endocrine rhythm may be partly maintained for some time. 4. Experiments with light and ultra‐violet irradiations indicate that with the majority of vertebrates exteroceptive stimuli dependent upon these processes are of primary importance in adjusting the cycle to changing periodic environmental conditions. 5. The evidence shows that the factors in question act through the intermediation of the central nervous system and the anterior pituitary body. 6. The cycle is liable to considerable modification by exteroceptive stimuli arising from the relations between the sexes and between the mother and her offspring. Thus ovulation in various species of vertebrates may depend upon stimuli normally arising from the male but which may be imitated by experimental methods. 7. Sexual display and courtship phenomena among various classes of animals, while undoubtedly in some species serving to keep the pairs together and thus securing a ‘marriage bond’, have the further and much more general function of promoting an effective synchronization of the male and female sexual processes, thus favouring successful procreation. 8. The synchronization is mainly effected by pituitary stimulation which is often mutual, the stimuli acting through the intermediation of the hypothalamus, as in the case of other stimuli. 9. Whatever the exteroceptive stimulus the anterior pituitary is the regulator of the gonadal function.

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Absence of Light and the Reproductive Cycle in the Guinea Pig

Cited by 27 publications

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The relationship between ovulation and the changes in thyroid gland activity that occur during the oestrous cycle in rats, mice and hamsters

The relationship between ovulation and the changes in thyroid gland activity that occur during the oestrous cycle in rats, mice and hamsters

Vaginal impedance measurement used for mating in the guinea-pig

Exteroceptive Factors in Sexual Periodicity

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