Effect of thiocyanate levels in milk on thyroid function in iodine deficient subjects.

To utilize the antibacterial effect of the lactoperoxidase system to prevent bacterial spoilage of raw milk it is necessary to increase the thiocyanate concentration of the milk. Thiocyanate has, however, a potent antithyroid effect which is enhanced by iodine deficiency. In this study the thyroid function has been studied, before and after 4 weeks daily administration of 250 ml of such treated milk, in 55 goitrous subjects living in an endemic goiter region of western Sudan. The iodine content was 0.1 mg/l and the thiocyanate content was either 3.6 mg/l (n 19) or 19 mg/l (n 36) in the milk. At the start of the experiment all subjects were iodine deficient with a urinary excretion of 40-50 micrograms/g creatinine. After 4 weeks daily intake of 4.75 mg of thiocyanate by way of milk the serum thiocyanate level increased by approximately 1.7 mg/l. Both at the beginning and at the end of the experimental period the serum levels of thyroxine, triiodothyronine and TSH were in the normal range for all subjects. After 4 weeks the TSH levels had decreased significantly, (from 2.6 +/- 0.2 to 2.1 +/- 0.2 mU/l, p less than 0.001) probably as an effect of the supplementary intake of iodine. The thyroid hormone levels remained unchanged during the experimental period. In conclusion, the intake of milk with an iodine concentration of 0.1 mg/l and a thiocyanate concentration of 19 mg/l does not have a negative effect on the thyroid function in iodine deficient subjects.

Intake of thiocyanate by way of milk and its possible effect on thyroid function.

The keeping quality of milk can be improved if the lactoperoxidase system is activated. To make such an activation efficient the thiocyanate concentration has to be increased. Since, however, thiocyanate has a potent antithyroid effect, thyroid function has been studied in 37 healthy individuals during 12 wk of daily intake of 8 mg thiocyanate by way of milk. The thiocyanate increased significantly in serum and reached a maximum value after 4 wk (+3.8 mg/1). The increased serum levels coincided with an increased excretion in urine (+ 4.8 mg/g creatinine). The levels of thyroxine, triiodothyronine, and thyrotropic hormone were all in the normal range at the beginning of the investigation and no significant changes were found during the experimental period. In conclusion, a daily intake of 8 mg thiocyanate by way of milk does not have any apparent effect on the thyroid function.

Alkylglycerols in bovine colostrum and milk in relation to precursor levels.

The concentrations of dihydroxyacetone phosphate (DHAP), glycerol-3-phosphate (GP), glucose and alkylglycerols were measured in bovine colostrum and milk. Concentrations of GP were higher in colostrum than in milk, and corresponded to intracellular concentrations at the onset of lactation. This suggests that GP equilibrates over the apical membrane at onset of lactation, which is believed to occur also in full lactation. The ratio of DHAP to GP showed a peak in colostrum that was more than twice that in milk, indicating that concentration changes in colostrum/milk were not caused by dilution. DHAP was positively correlated to metabolical compounds such as glucose and alkylglycerols. As DHAP is a required precursor for alkylglycerol synthesis, the positive correlation suggests that DHAP may be limiting for alkylglycerol synthesis and thus could explain the elevated levels of alkylglycerols found in colostrum.

Immunohistochemical studies on the development of prochymosin- and pepsinogen-containing cells in bovine abomasal mucosa.

1. Prochymosin- and pepsinogen-containing cells in abomasal mucosa were simultaneously localized by means of an indirect immunofluorescence technique with specific rabbit antibodies. 2. In the young milk-fed calves all the chief cells and several mucous neck cells produced both prochymosin and pepsinogen. 3. By elution of the first antibody and restaining of the same section it was demonstrated that the same cells were producing both prochymosin and pepsinogen. 4. In concentrate-fed calves and older cattle all chief cells and almost all mucous neck cells produced pepsinogen, while prochymosin was produced only from the chief cells situated in the upper part of the base in the gastric gland. 5. The number of prochymosin-containing cells was highly correlated to the milk-feeding of the animal. 6. The present data suggest that the non-differentiated cell in the neck region is initially capable of producing both prochymosin and pepsinogen during the proliferation phase to a mature chief cell, via mucous neck cell. The ability to produce prochymosin is however only retained if the mucosa is stimulated by milk-feeding. Dietary factors may thus be of importance for the differentiation of the gastrointestinal epithelium.

Incorporation of dietary 1-O-alkyldiacyl glycerols into tissue lipids of neonatal rats.

3H-[9,10]-1-O-alkyl-2,3-diacyl glycerols were administered per os to suckling rats at 1, 3, 6, 9 and 18 days of age. 12 h after administration the animals were killed and the distribution of the labelled material was analysed by whole-body autoradiography. The brown adipose tissue (BAT), intestine and liver showed the highest levels of label at all ages. The lipid content of BAT, intestine and liver were separated into lipid classes, which were analysed for their 3H levels. About 30% of the recovered label was found in the phospholipid fraction at all ages. Little of the administered dose was recovered as alkyl glycerols: 5% in the 1-day-old rat decreasing to less than 1.5% at 18 days of age, indicating that dietary alkyl glycerols only to a very limited degree are incorporated in tissue ether lipids in the young rat.