THE EFFECT OF THYROID ADMINISTRATION ON THE PANCREATIC AMYLASE ACTIVITY OF HYPOPHYSECTOMIZED AND INTACT RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 1373-1379 ◽  
Author(s):  
Madelaine O. Maykut ◽  
Margaret T. Nishikawara ◽  
R. E. Haist

The administration of desiccated thyroid gland to hypophysectomized rats prevented the marked atrophy of the pancreas which was consistently observed following hypophysectomy. Thyroid feeding at two dose levels led to a significant increase in the pancreatic amylase activity of hypophysectomized rats. This held whether the results were expressed as total activity or were given as activity per unit of body weight, per unit of pancreas, or per mg nitrogen. Except for the activity per unit of body weight, the amylase activity of the thyroid-treated hypophysectomized rats was significantly lower than the amylase activity in untreated, intact controls. In the thyroid-fed, hypophysectomized rats the amylase activity per unit of body weight was not significantly different from that of intact, untreated controls.Thyroid administration in intact rats resulted in a decrease in the pancreatic amylase activity.

1963 ◽  
Vol 41 (6) ◽  
pp. 1373-1379 ◽  
Author(s):  
Madelaine O. Maykut ◽  
Margaret T. Nishikawara ◽  
R. E. Haist

The administration of desiccated thyroid gland to hypophysectomized rats prevented the marked atrophy of the pancreas which was consistently observed following hypophysectomy. Thyroid feeding at two dose levels led to a significant increase in the pancreatic amylase activity of hypophysectomized rats. This held whether the results were expressed as total activity or were given as activity per unit of body weight, per unit of pancreas, or per mg nitrogen. Except for the activity per unit of body weight, the amylase activity of the thyroid-treated hypophysectomized rats was significantly lower than the amylase activity in untreated, intact controls. In the thyroid-fed, hypophysectomized rats the amylase activity per unit of body weight was not significantly different from that of intact, untreated controls.Thyroid administration in intact rats resulted in a decrease in the pancreatic amylase activity.


1955 ◽  
Vol 33 (1) ◽  
pp. 380-384
Author(s):  
B. Kinash ◽  
R. E. Haist

When sufficiently large amounts of desiccated thyroid gland were administered to intact or hypophysectomized rats there was an increase in the weight of the pancreas, weight of the islets of Langerhans, and islet weight per unit of body weight. In intact rats the concentration of islet tissue in the pancreas was not significantly altered, but in hypophysectomized animals the concentration of islet tissue in the pancreas was reduced because of the large increase in pancreas weight. The great reduction in pancreas weight occasioned by hypophysectomy was to a large extent prevented by the administration of desiccated thyroid gland.


1955 ◽  
Vol 33 (3) ◽  
pp. 380-384 ◽  
Author(s):  
B. Kinash ◽  
R. E. Haist

When sufficiently large amounts of desiccated thyroid gland were administered to intact or hypophysectomized rats there was an increase in the weight of the pancreas, weight of the islets of Langerhans, and islet weight per unit of body weight. In intact rats the concentration of islet tissue in the pancreas was not significantly altered, but in hypophysectomized animals the concentration of islet tissue in the pancreas was reduced because of the large increase in pancreas weight. The great reduction in pancreas weight occasioned by hypophysectomy was to a large extent prevented by the administration of desiccated thyroid gland.


1980 ◽  
Vol 87 (1) ◽  
pp. 65-71 ◽  
Author(s):  
MASAYOSHI KUMEGAWA ◽  
NORIHIKO MAEDA ◽  
TOSHIHIKO YAJIMA ◽  
TAISHIN TAKUMA ◽  
EIKO IKEDA ◽  
...  

The effects of cortisol (10 μg/g body weight) and l-thyroxine (T4; 0·2 μg/g body weight) on the activity of parotid gland amylase in young rats were investigated. Administration of cortisol or T4 for 5 consecutive days from day 5 after birth caused the precocious appearance of amylase, T4 having almost twice the effect of cortisol. Cortisol and T4 did not have synergistic effects. In thyroidectomized-adrenalectomized rats, T4 increased amylase activity but cortisol did not. The increase in enzyme activity after day 20 was much less in rats thyroidectomized on day 10 than in rats adrenalectomized on day 10. These results suggest that T4 has a direct effect on the early increase of amylase activity (days 15–25) and that the action of glucocorticoid requires the presence of endogenous thyroid hormones. The hormone-induced level of amylase in intact rats was less than that of normal adult rats. Forced weaning of intact rats resulted in a further increase in amylase activity, suggesting that further amylase accumulation (after day 25) may be due to dietary factors.


1955 ◽  
Vol 33 (3) ◽  
pp. 248-255 ◽  
Author(s):  
N. R. Stephenson ◽  
W. P. McKinley ◽  
P. J. Kavanagii

The ability of the thyroid gland of intact weanling rats to collect injected radioactive iodine was diminished by inclusion of a small amount of iodinated casein in the diet. The administration of exogenous thyrotrophin increased the thyroidal uptake of I131 in rats treated in this manner. Both the degree of inhibition of the thyroid and the ability of the animals to differentiate between dosage levels of thyrotrophin were dependent upon the amount of iodinated casein in the diet. Graded doses of thyrotrophin provided a linear log dose –response line over the range 0.01 to 0.08 U.S.P. units. The response approached a maximum value at dose levels above 0.16 U.S.P. units. The thyroid gland of the female weanling rat retained, on the average, significantly more radioactive iodine than that of the male weanling rat when stimulated by thyrotrophin. Although the hormonal response was not correlated with the body weight of the rats within dosage groups, more precise assays were obtained by equalizing the total weight of the rats in each dosage group before the assay. Relatively large doses of I131 appeared to have an adverse effect on the precision of the assay but did not influence the response to thyrotrophin.


1955 ◽  
Vol 33 (1) ◽  
pp. 248-255
Author(s):  
N. R. Stephenson ◽  
W. P. McKinley ◽  
P. J. Kavanagii

The ability of the thyroid gland of intact weanling rats to collect injected radioactive iodine was diminished by inclusion of a small amount of iodinated casein in the diet. The administration of exogenous thyrotrophin increased the thyroidal uptake of I131 in rats treated in this manner. Both the degree of inhibition of the thyroid and the ability of the animals to differentiate between dosage levels of thyrotrophin were dependent upon the amount of iodinated casein in the diet. Graded doses of thyrotrophin provided a linear log dose –response line over the range 0.01 to 0.08 U.S.P. units. The response approached a maximum value at dose levels above 0.16 U.S.P. units. The thyroid gland of the female weanling rat retained, on the average, significantly more radioactive iodine than that of the male weanling rat when stimulated by thyrotrophin. Although the hormonal response was not correlated with the body weight of the rats within dosage groups, more precise assays were obtained by equalizing the total weight of the rats in each dosage group before the assay. Relatively large doses of I131 appeared to have an adverse effect on the precision of the assay but did not influence the response to thyrotrophin.


1980 ◽  
Vol 86 (3) ◽  
pp. 497-500 ◽  
Author(s):  
MASAYOSHI KUMEGAWA ◽  
NORIHIKO MAEDA ◽  
TOSHIHIKO YAJIMA ◽  
TAISHIN TAKUMA ◽  
EIKO IKEDA ◽  
...  

The effect of l-thyroxine (T4) on amylase activity in the developing rat pancreas has been investigated. Administration of T4 (0·2 μg/g body wt) alone to intact rats on days 5–10 after birth did not induce pancreatic amylase but the enzyme was induced significantly by daily injection of cortisol (10 μg/g body wt) alone into intact rats over the same period. In thyroidectomized, adrenalectomized rats pancreatic amylase was not induced by the injection of cortisol alone but it was induced by the administration of cortisol plus T4. Increase in enzyme activity was much less in thyroidectomized animals than in intact animals. These results suggested that T4 does not have a direct effect in increasing pancreatic amylase activity but plays a permissive role in increasing enzyme activity.


1972 ◽  
Vol 70 (1) ◽  
pp. 167-174 ◽  
Author(s):  
Artur Ber

ABSTRACT Hypophysectomy was performed at the same time as ovariectomy in 19 rats aged 6 weeks; in addition a fragment of the animal's own ovary was implanted into the greater omentum. The graft took but there was complete cessation of the growth of the implant and a decrease in body and uterine weights as compared to 15 ovariectomized controls of the same age killed after one month. This shows that the pituitary is indispensable for the growth of ovarian implants but not for their take. In 84 spayed rats aged 3 weeks with ovarian implants, methallibure (6 mg/day in a 0.2% solution of Tween 20) was given by gavage during one month. Some of them were treated with PMSG (20 IU/day), HCG (20 IU/day) or with oestradiol benzoate (0.05 mg/day) only or in combinations. As controls, there were 74 spayed rats with ovarian implants, seven of which received Tween 20, and 67 were untreated. No differences were found between the two control groups. Methallibure alone caused arrest of the development of the implants and uteri and a decrease in body weight. In the methallibure treated animals HCG stimulated the growth of the implant which was, however, smaller than that in the controls, while PMSG restored the weight of the implant even above that of the control rats. Oestradiol benzoate caused a further diminution in the size of the implants but augmented considerably the influence of HCG on the implants. It had no effect on the weight of the implant in rats treated with PMSG. It is concluded that FSH is the principal implant growth-promoting factor and that oestrogens appear to act in two directions. They decrease the gonadotrophin output from the pituitary thus inhibiting the growth of the implants, but in the presence of gonadotrophins they act directly on the implants, promoting their development.


1985 ◽  
Vol 104 (2) ◽  
pp. 435-443 ◽  
Author(s):  
A. N. Janes ◽  
T. E. C. Weekes ◽  
D. G. Armstrong

SummaryTwo groups of six sheep were fed either dried-grass or ground maize-based diets for at least 4 weeks before slaughter. Samples of the small intestinal mucosa and spancreatic tissue were assayed for a-amylase, glucoamylase, maltase and oligo-l,6-glucosidase.The pancreatic tissue contained high activities of α-amylase and much lower activities of glucoamylase, maltase and oligo-1,6-glucosidase. There was no effect of diet on the specific activities of any of these enzymes in the pancreatic tissue.The activity of α-amylase adsorbed on to the mucosa of the small intestine was greatest in the proximal region of the small intestine, the activity generally declining with increasing distance away from the pylorus. There was no diet effect on the absorbed α-amylase activity.Similar patterns of distribution along the small intestine were observed for maltase, glucoamylase and oligo-1,6-glucosidase with the highest activities in t he jejunum. There was no overall effect of diet on glucoamylase or maltase specific activities and glucoamylase total activity, although the total activities of maltase and oligo-1,6-glucosidase were significantly greater for the sheep fed the ground maize-based diet (P < 0·05).It is suggested that ruminant animals may be capable of digesting large amounts of starch in the small intestine through an adaptation in the activity of the host carbohydrases.


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